Perineural liposomal bupivacaine for postoperative pain control in patients undergoing upper extremity orthopedic surgery: A prospective and randomized pilot study

Background: Upper extremity surgery is commonly performed in the ambulatory setting and is associated with moderate to severe postoperative pain. Methods: Patients scheduled for upper extremity orthopedic surgery with a peripheral nerve block were randomized to receive either an ultrasound-guided single-injection supraclavicular block or ultrasound-guided median, ulnar, and radial nerve blocks (forearm blocks) performed at the level of the mid to proximal forearm with liposomal bupivacaine (Exparel) combined with a short-acting supraclavicular block. A sham block was performed in an attempt to blind enrollees in the control group. We administered the EuroQol 5D-5L questionnaire preoperatively and on postoperative days 1-3 and considered the results the primary outcome of our investigation. Block procedure times, postanesthesia care unit (PACU) length of stay, instances of nausea/vomiting, need for narcotic administration, and patient satisfaction were also assessed. Results: We observed no significant differences in postoperative EuroQol scores between the 2 groups and no significant differences in patient demographics, PACU length of stay, or side effects in the PACU. In some instances, the short-acting supraclavicular block resolved in the PACU, and these patients reported higher pain scores and required titration of analgesics prior to discharge. Conclusion: Larger prospective studies are needed to determine the safety and efficacy of liposomal bupivacaine in patients undergoing upper extremity surgery. Liposomal bupivacaine is currently only approved for local anesthetic infiltration use

Characterization by electrospray ionization and tandem mass spectrometry of rhamnolipids produced by two Pseudomonas aeruginosa strains isolated from Brazilian crude oil

In this work, biosurfactants produced by two Pseudomonas aeruginosa strains isolated from Brazilian crude oils were identified by proton nuclear magnetic resonance ((1)H NMR) and further characterized by mass spectrometry (MS) coupled with electrospray ionization (ESI) and tandem mass spectrometry (MS/MS) analysis in positive mode and their surface activities evaluated. Mono-rhamnolipids and di-rhamnolipids were identified for both isolates, but the most abundant were found to be mono-rhamnolipids. The similarity of rhamnolipids produced by the two strains was in good agreement with their surface activities. Both biosurfactants exhibited similar aqueous solution surface tensions, high emulsification indexes and critical micelle concentration values. The results obtained show that ESI-MS and MS/MS analysis alone provide a fast and highly specific characterization of biosurfactants produced by microbial strains.This work was supported by PARTEX OIL AND GAS. The authors acknowledge the financial support from Fundacao para a Ciencia e a Tecnologia for the Pest-C/CTM/LA0011/2011 and doctoral research grant of Jorge F.B. Pereira SFRH/BD/60228/2009